Australia's beloved wombats are being eaten to death by mange-inducing Sarcoptes scabiei mites, and their homes are the suspected transmission path. To address this crisis we need to know more about the insides of wombat burrows, a topic that has proven very hard to explore. A robot engineer and wombat expert have come together to design a robot, named WomBot, up to the task, describing its preliminary success in SN Applied Science.
Adult bare-nosed wombats are expert social distancers, coming together only to mate, which should protect them against infectious disease. However, they have one weakness in this regard, they move burrows every four to 10 days, and sometimes other wombats will occupy a burrow while its usual occupant is elsewhere. It is suspected the mite survives in these burrows between occupants, waiting to pounce on the next visitor. For all their toughness, wombats cannot resist the mite, and once infected die a slow and itchy death if not treated.
The exploration of wombat burrows began in the 1960s when a teenager broke out of his boarding school to go searching underground. It hasn't advanced far since – most adults are too big to fit down wombat holes. Moreover, in contrast to the sadly inaccurate accounts of wombats herding animals into the safety of their burrows during Australia's recent bushfires, bare-nosed wombats don't much like to share. Peaceable creatures above ground, there are rumors of wombats turning aggressive below, using their famously mighty rumps to squash intruders against the burrow walls.
Furthermore, few vehicles can handle the rough terrain of a wombat burrow, so Dr Robert Ross of LaTrobe University decided to build one that can. WomBot runs on continuous tracks, like the tanks wombats are sometimes compared to, allowing it to handle inclines of up to 22 degrees. With a top speed of just 0.15 m/s (0.34 mph), it is the opposite of speedy, but it carries multiple sensors that reveal subterranean conditions.
WomBot's explorations revealed Tasmanian burrows in September stay around 11∘ C throughout a 24-hour cycle with 85–95 percent humidity – perfect for mites – although they warmed up a little with wombat body heat. Ross and Dr Scott Carver of the University of Tasmania estimate the mites could survive for nine to 10 days near the burrow entrance and 16–18 days deep inside, waiting for their next victim
"Our findings indicate that the environmental conditions within wombat burrows may facilitate sarcoptic mange transmission by promoting mite survival,” Ross said in a statement. “WomBot could potentially be used to help reduce the spread of sarcoptic mange by delivering insecticide or ensuring burrows are empty before being temporarily heated in order to eradicate mites."
Ross told IFLScience the study was conducted in a part of Tasmania where many wombats have recently died from the mange. Consequently, despite exploring 30 burrows there was only one wombat/WomBot encounter. “Wombats are nocturnal and we were exploring during the day, so it was asleep,” Ross said. “We backed out without disturbing it.”
WomBot is remotely controlled, rather than being autonomous, but the team found high-powered Wifi penetration dropped to zero within a few meters of the burrow entrance. Instead, they went old school, transmitting instructions and collecting data via an ethernet cable WomBot spooled behind it like Theseus in the Labyrinth.
WomBot is so specifically designed for the needs of wombat burrows it would not suit most other underground species, Ross told IFLScience, adding: “we'd need to scale it down to explore rabbit burrows.”
Instead, future plans involve collecting dirt samples that can be checked for mites, and constructing 3D reconstructions of the insides of wombat holes.